Freitag, 29. März 2013

a few days ago I had the idea to publish the tutorial as a poster, with all the circuits on it. This was the fastest and easiest I could do. So here it is.

It's not really a tutorial. Because for a tutorial you need much more time for writing the instructions. It's a poster. I have attached two pdf- files with the poster so you can print it in a4 or a3, furthermore I also have this picture in very high resolution attached, so you can view and print it in any size you want.

Circuits of a laser cutting and engraving machine, based on the Thunderlaser DF212 or DF211 controller. Designed for the chinese K40 series (40W).

I hope this is enough. You can see how the parts are connected. I have a short description in the top-left corner. But I think this should be absolutely enough for people who have no plan how to connect the parts :)

In the following picture you can see the interior of my machine. I'll tidy it up and make it look better ASAP.

The laser power supply is not inside the case yet. I have glued heatsinks to the drivers. They become really warm during long jobs. More pictures will come soon. A video of my machine in in action will come maybe this weekend or next week (because I need to make a seperate Youtube account).

Dienstag, 26. März 2013

many users have the problem that their K40 machine destroys itself as an effect of the Moshi 2013 software. But a few days ago someone showed me a fix which could be the solution for the problem in less than 5 minutes!

Initial Situation: after turning on the machine, the motors don't move, machine is not accessible.

You can download the free repair tool on https://www.mediafire.com/?1ho1peojpqejhks

1) Unzip archive
2) Copy the files to: C:/Moshidraw (folder name can vary)
3) Connect the machine with your PC and turn it on.
4) Run the tool (maybe as administrator (right click -> run as administrator)). Wait until "Can Use" is displayed. Then you can start the fix by clicking on "Repair". This takes less than a second.

The machine should now work again. Just restart it. To prevent this damage again, uninstall Moshi 2013 and only use your machine with Moshi 2012!

I tried this with my mainboard, but since I modified my machine I haven't had any possibility to test the board. Please write a short comment if it has worked or not :)

Samstag, 16. Februar 2013

Disclaimer:All information supplied in this document has been compiled to the best of my knowledge, nonetheless I cannot guarantee that everything is correct and remains that way. Everybody is responsible for his own actions and suitable safety measures should be complied with when handling class IV laser equipment!

Usually the laser should be pre-aligned by the manufacturer, however it can happen that the mirrors can get misaligned during transport. Sometimes a small or even larger adjustment has to be made in order to get the best out of the machine.

Caution: Only operate the laser with the lid of the machine closed. Never activate a test pulse with the lid open, especially after having made an adjustment to the mirrors, regardless of how little it has been.

To obtain consistent engraving and cutting results, the mirrors have to be adjusted in a way that the laser beam always hits the movable laser head in exactly the same spot (see Figure 1). For example, if the mirrors are not correctly adjusted, the entrypoint of the laser into the head drifts with increasing distance to the second mirror. Depending on the magnitude of misalignment a part of the beam may not even hit the opening of the laser head anymore, which in turn means that not all of the laser power actually reaches the material that is to be cut or engraved. In this case the depth of the engraving or cutting decreases with increasing distance to the second mirror.

Figure 1: Schematic of the laser path and the role of the mirrors for correct alignment

It is not absolutely necessary that the beam hits all of the mirrors exactly at their center. It is more important that the actual point of impact is the same for all X and Y positions and that this point is not as close to the edge as to actually “lose” a part of the beam.

Alignment procedure:
Several HowTo’s and manuals advise the usage of masking tape or similar material wich can be directly stuck onto the mirrors. With my bigger G350 laser the manufacturer even included double-sided tape to be used for alignment. This however has the big disadvantage that smoke is produced in the direct vicinity of the mirrors, which can soil and even damage them. In case you have nothing else available but masking tape it is recommended to use several layers of it so that not all layers are burned through and the smoke does not even reach the mirror. Of course this testing is to be done with as little laser power as possible.

The best way to check for the exact impact point of the beam on the mirrors is using thermal paper with very low laser power. Most receipts (e.g. from gas-stations, supermarkets, etc) are printed on thermal paper and can be used for this purpose regardless of how much is printed on them. The advantage: Thermal paper gets a dark discoloration even before it starts to burn!

Stick the thermal paper to the mirror with adhesive tape but take care not to cover the part where you expect the beam to hit with plastic as well, as this will definitely smolder. Adjust the laser power to the absolute minimum and increase it slightly while firing short test bursts. Take care to stop increasing the power once you see that the paper shows discoloration. If the paper is burning, decrease the power again or use shorter bursts, exchange the thermal paper for a new piece. Once the appropriate laser power has been found it is to remain unchanged during the alignment process.

The position of the beam on the first mirror is pretty irrelevant s long as the complete beam is reflected towards the second mirror. It usually is sufficient to test that the beam does not hit too far off-center .If the beam hits too close to the border of the mirror either the mirror mount or the laser tube have to be adjusted slightly. Remove the paper from mirror 1 after this short test.

In the first step of the alignment procedure the aim is to adjust the first mirror in a way that the beam always hits the second mirror in the very same spot (see Figures 2.1 and 2.2). In order to see the point at which the beam hits the mirror, a piece of thermal paper is placed on top of mirror 2.

Figure 2.1: Mirror 2 close to mirror 2

Figure 2.2: Mirror 2 further away from mirror 1

The best way to achieve this is to use position the laser head in a way that the distance between the mirrors 1 and 2 is minimized, then firing a short test shot. Then, after increasing the distance between the two mirrors, a second test shot is fired. In a well aligned machine both dots are superimposed on each other. If this is not the case some adjustments need to be made on mirror 1. The adjustment screws have to be turned only very slightly, as depending on which adjustment system is present in your machine, even a whole rotation of the screw can change de angle of the mirror by several degrees. I will explain the procedure briefly using the type of mirror mount present in my machine. The type you might find in yours might differ, but the three-screw design seems to be the most popular one. Some mounts might have screws in different positions, so this guide may not apply exactly to those models. I really urge you to use your brain here and exercise the necessary safety precautions (do not operate the machine with the cover open, wear protective eyewear). I would suggest checking the coarse adjustment using a short distance between the mirrors first and then increasing the distance for a finer adjustment. Please refer to Diagram 3.1 as to how the screws will impact the beam alignment. It usually is necessary to do subsequent tests of short and increased distances with replacing the thermal paper in between, as every adjustment on the mount will affect the positions of the dot at both short and longer distances.

The mirror mount depicted in Figure 3.1 shows the mirror mount found in my DC-K40, which features three screws for adjustment. Screws A and C make adjustments in one plane only (A horizontal and C vertical) whereas adjustments of screw B will adjust both planes at the same time. The mirror mount in my larger G350 machine were designed differently but had similar placements of the adjustment screws.

When the first mirror is adjusted in a way that the laser beam hits exactly the same spot on mirror 2 regardless of the distance between the mirrors, the same procedure is done to adjust the second mirror in order to get superimposing spots on the in the lens mount assembly. To do this it is sufficient to fix the thermal paper on the hole on the laser head where the laser is supposed to enter. Here again it is tested whether the position is superimposed regardless of distance between mirror 2 and the laser head, best done again with first short and then longer distance. Depending on the type of laser head the third mirror inside can also be adjusted, which is not the case in the small DC-K40 machines. If you happen to have a laser head with adjustable mirror, remove the lens holder and place the thermal paper on the bottom of the laser head and check whether the dot is centered correctly. If not, adjust the mirror in the laser head accordingly.

I have documented the whole procedure in a video, which is in editing right now. Wi will be accessible here soon... [INSERT LINK]

Freitag, 25. Januar 2013

This week all important parts arrived. I'm still waiting for the limit switches and some litz wire.

Even though they are important, I was able to start with the easiest things. I think I'm going to publish the whole tutorial at once. I think the work will be finished in the week between 11.2. and 18.2., maybe earlier.

On this video you can see how one axis moves slowly. The x and y axis already work. The steppers run much more silent than before with the Moshidraw controller.

Unfortunately the limit switches haven't arrived yet so I have to turn off the machine before the laser head reaches the limit and crashes. So I can't control the machine with the arrow keys yet.

Sonntag, 20. Januar 2013

How to make a "cover safety switch"

in this tutorial I show you how you can upgrade your laser's security. As I already mentioned, it's not safe to operate the laser while the cover is open.
With a microswitch, some wires and 20minutes of work you can install the switch which turns off the laser beam when the cover isn't closed.

Level: easy
Costs: less than 5€

What you need:

microswitch (2-3€ on ebay)

cable

electrical tape (duct tape)

thin and long screws + screw nuts + washers

Tools:

drilling machine with fitting drill for screws

soldering gun with tin-solder

in general: screwdrivers and tongs

Here is the how to:

(Please check if the switch is set right before you attach the switch to the machine!)

Your machine is now "one step safer".

Even though it istn't completely safe, it complies with one of the most important laser safety rule now.

Donnerstag, 10. Januar 2013

My unboxing experience with the DC-K40 was similar to that of fasensu, albeit mine was better packed and sent directly from Germany. For this reason, I am going to spare you with a similar unboxing story, but I think I might share the onboxing of my newer purchase, the larger G350 machine.The item specifications listed the machine to be around 60x60x90cm with a weight of 65kg. I did know that I had to expect a crate to be delivered, but was quite astonished with what DHL unloaded in front of my door.

All in all: 116kg of Chinese goodness shipped form the UK in 3 days. Luckily I quickly found someone to help me carry the box to the elevator and then into my flat.

Everything was pretty neatly packed and undamaged. All of the acessories were stuffed into the compartment under the unmotorized up/down-table, air pump and rotary device were packed in bubble-wrap like hell (the rotary device alone had 16 meters (!) of bubble wrap around it.As I did not really have time to complete the unboxing mostly because it could not be done alone, I dit not take further pictures of what was included, so here you are with the final result (the bigger machine of course):

Hi everyone,I came into contact with
fasensu, the initiator of this blog, on a German message board
(laserengravers.com) and we started to have a pretty vivid discussion
concerning several aspects of DC-K40 and basically all cheap China lasers in general.
I started using a similar laser just two months ago and liked the possibilities
of laser material processing so much that I just upgraded to a bigger (and of
course overall better) unit.I made quite a bunch of
modifications to my small DC-K40-type machine and was already compiling a manuscript
documenting the various changes and additions, of which I think many are interesting
for other users as well (Honeycomb table, Air-Assist, Red Dot, LED illumination,
etc.). As of now the document is still in the making and should be ready to be “let
loose” to a wider audience in about two to four weeks, but I might be able to
release it bit by bit on this blog sooner. I hope that I will be finished with
the English translation in time, as the intended version was for the above
mentioned message board which is in German.Having covered the reasons
for me joining this blog let me briefly introduce myself. I am a Biomedical
Scientist, or aspiring to be one to be honest. I have been working on my PhD
thesis for a market-leading German Biotech company for about 18 months but had
to quit at that point for various reasons. Right now I am trying to find a new
group to join and to start with another project leading to my PhD. I have
always been a DIY-person and was always eager to try new thing, especially if
some kind of technical device is involved. The reason for me getting into the “laser
business” is a bit whacky: I was playing “Settlers of Catan” with a few friends
of mine and we criticized the newer versions’ plastic figurines instead of “ye
olde” wooden ones. Somehow the idea “let us make a Settlers version completely
from wood” sparked into existence, two weeks of research later I was the proud
owner of a DC-K40-type laser ;-)That is about it, stay
tuned ;-) My modified DC-K40 with its bigger brother, the G350. And yes, the thing in the back is a Sega Naomi Arcade machine, and yes, I have the laser in my living room ;-)